Particulate emissions have been the focus of technical development in internal combustion engines for quite some time since particulates are believed to be carcinogenic. A continual reduction of the quantity of particulates emitted is desired and driven by corresponding legislation.
In the case of internal combustion engines with direct injection, fuel is injected directly into the combustion chamber (piston, cylinder) of the internal combustion engine and ignited during a revolution cycle. In this case, the precise times of the beginning of injection of the fuel into the combustion chamber and of the ignition are normally determined using the significant operating parameters of the internal combustion engine, such as engine speed and engine load. In the prior art, the times are generally chosen in such a way that low fuel consumption is achieved for a given engine power output.
In one example, some of the above issues may be addressed by a control method comprising, a starting time for an injection of fuel into a combustion chamber of the internal combustion engine in accordance with operating parameters of the internal combustion engine. Here, the starting time can be determined in a conventional manner and, in particular, in accordance with the engine speed and engine power output of the internal combustion engine. In addition, a first engine load of the internal combustion engine may be determined at a first time. This first time can be before or after the determination of the starting time or, alternatively, simultaneous with the determination of the starting time. At a later, second time, a second engine load of the internal combustion engine may be determined. As a result, there are two values available for the engine load of the internal combustion engine at different times, and these are then compared with each other. A delay time period may be determined in accordance with a result of the comparison of the first and the second engine load. Injection of the fuel into the combustion chamber of the internal combustion engine may then carried out, beginning at a time offset from the starting time by the delay time period.
In another example, a method includes temporarily delaying a start of injection of directly injected fuel to an engine cylinder in response to an increase in engine load; but temporarily advancing the start of injection of directly injected fuel to the engine cylinder in response to a decrease in engine load. Such operation is in contrast with extended timing adjustments responsive to engine load for steady-state operation. In this way, smoke production may be reduced, while maintaining steady-state efficiency performance.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.